This invention relates to ultrasonic humidifiers. More particularly, it relates to an ultrasonic humidifier which is improved to be free from the drawbacks that when the water level in its atomizing chamber, which is so designed to maintain a constant water level even when the humidifier itself is inclined by the rolling of a structure such as a vehicle or a ship where it is installed, is increased, the quantity of water atomized by the ultrasonic vibration board is decreased, or it becomes impossible for the ultrasonic vibration board to atomize the water.
A conventional ultrasonic humidifier as shown in FIG. 1 comprises: an atomizing chamber 2 provided on one side of the inside of a box-shaped body 1. The atomizing chamber 2 has a discharge outlet 2a provided on top of the box-shaped body 1 and an ultrasonic vibration board 4 secured to the bottom plate 3 of the atomizing chamber 2. A water supply chamber 5 is provided on the opposite side of the inside of the box-shaped body 1; the water supply chamber 5 incorporating a cartridge type water supply tank 11.
A valve rod receiving chamber 6 communicates with the bottom of the water supply chamber 5 at one side, and an internal space is provided below the common bottom of the atomizing chamber 2 and the water supply tank chamber 5 including the valve rod receiving chamber 6. In the internal space, an ultrasonic wave oscillator 7 adapted to apply an ultrasonic wave signal to the vibration board 4 and an air blower 8 are provided.
The flow of air caused by the blower 8 is allowed to flow upwardly along a first air flow path 9 and downwardly along a second air flow path 10 as indicated by the arrows. The water supply tank 11 has a thin neck 12 protruding into the valve rod receiving chamber 6 and a water outlet 13 is formed in the thin neck 12. The outlet 13 is closed by a valve 15 on top of the valve rod 14 with the aid of the elastic force of a spring 16. When the lower end of the valve rod 14 reaches the bottom of the valve rod receiving chamber 6, the valve rod 14 is pushed upwardly as shown in FIG. 1, to open the outlet 13. The valve rod receiving chamber 6 communicates with the atomizing chamber 2 through a horizontally extending water delivering path 17. Therefore, the level of water above the ultrasonic vibration board 4 of the atomizing chamber 2 is determined by the height of the water oulet 13, and the water level in the atomizing chamber 2 is automatically maintained constant even if the water in the atomizing chamber is consumed by atomization.
In a conventional humidifier, the valve rod receiving chamber 6 communicates with the atomizing chamber 2 through a straight water delivery path 17, the distance between the two chambers being short, as shown in FIG. 2. Therefore, the conventional humidifier is disadvantageous in the following points. Consider the case where the humidifier is installed, for instance, on a structure such as a vehicle or a ship. Whenever the structure is inclined, the body 1 is also inclined. When the water level in the atomizing chamber 2 is decreased by the inclination of the body 1, the water in the tank 11 is allowed to flow into the atomizing chamber 2 through the water outlet 13 of the tank 11, which is in the valve rod receiving chamber 6.
Accordingly, even if the body 1 is restored to be horizontal, the water level cannot be restored to the initial level; that is, the new water level caused by the inclination is higher than the predetermined one. As a result, it is difficult to sufficiently transmit the vibration of the board 4 to the water surface. Accordingly, the atomization of the water is insufficient, and at worst it cannot be effectuated.